I have tested this item ✅ successfully on f31bb1b

didn't get Failure, where to "enable full php error reporting"?

System information

3.8.2-dev
Multilanguage Site
macOS Sierra, 10.12.6
Firefox 56 (64-bit)

MAMP 4.1.1

• PHP 7.0.15
• MySQLi 5.6.35

Set error reporting to development in global config (it should be at that whenever you are testing)
Then make sure the filters are set exactyl as in the image

I understand that this PR hides warning, but only one menu item should has level=0, its Root.

I can not reproduce this warning on fresh joomla.

If we hide that error by this PR then we can not get any information that our/your table #__menu is corrupted. probably this is the wrong approach. I have changed my mind.

I confirm that I do not get this error on a clean staging.

@brianteeman Error reporting was set on "Maximum", select "Development" didn't get Failure too.

System information

3.8.2-dev
Multilanguage Site
macOS Sierra, 10.12.6
Firefox 56 (64-bit)

MAMP 4.1.1

• PHP 7.0.15
• MySQLi 5.6.35

@brianteeman You should click the rebuild button, which will repair #__menu table.
After that you should not see more warning.

nope it is still there

I suspect you have incorrect column parent_id too.

You can try to find the smallest set of rows (by filters) that generates warning and then open and save each one. This should fix parent_id.

Other way, could be danger, you can go to phpmyadmin and look for rows with parent_id = 0, (except 'Root') and change it to 1

Above rows with id 497 and 498 have wrong parent_id. I'm curious when/why they are corrupted.

opensing and resaving fixed the parent_id - rebuild did not

Can you precise Joomla version or ~date when above rows was created, with parent_id = 0.

reminder for @brianteeman

I have tested this item ✅ successfully on f31bb1b

Code review

Ready to Commit after two successful tests.